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  3. Positive association of low-level environmental phthalate exposure with sperm motility was mediated by DNA methylation: A pilot study

Positive association of low-level environmental phthalate exposure with sperm motility was mediated by DNA methylation: A pilot study

  • Chemosphere. 2019 Apr;220:459-467. doi: 10.1016/j.chemosphere.2018.12.155.
Meiping Tian 1,  Liangpo Liu 2,  Jie Zhang 2,  Qingyu Huang 2,  Heqing Shen 3
Affiliations

Affiliations

  • 1 Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
  • 2 Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
  • 3 Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. Electronic address: [email protected].
PMID: 30594797 DOI: 10.1016/j.chemosphere.2018.12.155
Abstract

Accumulating evidence indicates that phthalate exposures may affect human semen quality. Epigenetic modifications such as DNA methylation might be linked chemical exposure and spermatogenesis epigenetic reprogramming. In the present study, we investigated associations between phthalate exposures, DNA methylation and sperm quality in undergoing fertility assessment male population. Urine was used for phthalate exposures monitoring, six selected metabolites (i.e., monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP), mono-(2-ethylhexyl) phthalate (MEHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP)) were measured by using HPLC-MS/MS. Sperm quality parameters were determined by computer-assisted semen analysis (CASA). Sperm DNA methylation patterns (long interspersed nuclear element-1(LINE-1), H19 and LIT1) were analysed employing high-melting resolution (HRM) PCR. Urinary MMP, MEHP, MEOHP, sum of DEHP metabolites (∑DEHP) and sum of selected phthalates metabolites (∑PAEs) were significantly positively associated with sperm motility. Sperm LINE-1 DNA methylation were found to be negatively associated with ∑DEHP exposure and sperm quality (ejaculate volume, total sperm number and motility). Epigenetic modification LINE-1 DNA methylation demonstrated mediating effects in association between DEHP exposure and sperm motility, and 20.7% of the association was mediated by serum LIEN-1 DNA methylation. These results extend the previous studies in association between phthalate exposures and classical semen parameters, mainly of inverse association, and sperm DNA methylation may be linked phthalate exposures and male reproductive health outcome.

Keywords

DNA methylation; LINE-1; Phthalate exposure; Sperm quality.

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